Shoulder dystocia occurs after delivery of the head. After McRoberts maneuver and suprapubic pressure fail, which subsequent maneuver delivers the posterior shoulder FIRST, thereby providing the quickest resolution of the dystocia?

• A Rubin II maneuver — pressure on posterior aspect of anterior shoulder to adduct it
• B Delivery of posterior arm — sweeping the posterior arm across the fetal chest and delivering the arm ✓
• C Woods screw maneuver — pressure on anterior aspect of posterior shoulder to rotate the fetus
• D Zavanelli maneuver — replacing the fetal head followed by emergency cesarean section

Explanation

Delivery of the posterior arm is widely regarded as the most effective secondary maneuver for shoulder dystocia, with the highest success rates (84–90%) compared to rotational maneuvers. By sweeping the posterior arm across the fetal chest and delivering it, the shoulder diameter is effectively reduced and the posterior shoulder is brought under the pubic symphysis, resolving the dystocia rapidly. The Rubin II (A) and Woods screw (C) are rotational maneuvers — they reduce the bisacromial diameter by rotating the shoulder to the oblique diameter, but are slower and require expertise. Zavanelli (D) is a last-resort procedure with significant fetal and maternal morbidity, only when all other maneuvers fail.

Reference: Williams Obstetrics, 26th ed.

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Written and medically reviewed by the StethoPrep medical team.